[Idiopathic plasmacytic lymphadenopathy with polyclonal hyperimmunoglobulinemia with elevated level of serum interleukin-6].

A 38-year-old male was admitted in January 1984 due to lymphadenopathies with hyperimmunoglobulinemia with a serum IgG level of 2,872 mg/dl. Following this, he was observed as an outpatient in regard to lymphadenopathies of unknown origin. In 1989, after the fourth lymph node biopsy he was diagnosed as having idiopathic plasmacytic lymphadenopathy with polyclonal hyperimmunoglobulinemia. At that time his serum IgG level was 8,090 mg/dl. The elevated serum interleukin-6 (IL-6) level, up to 21.1 pg/ml, was particularly interesting, because IL-6 is involved in the oncogenesis of plasmacytoma/myeloma. The patient also had thrombocytosis, hematuria, and a serum increased level of C reactive protein which seemed to be related to the effects of IL-6 i.e. thrombopoiesis, induction of the proliferation of mesenchymal cells, and induction of the production of acute phase proteins by hepatocytes, respectively. Even though he displayed no outward symptoms before and after treatment with prednisolone and melphalan, elevated immunoglobulin levels were still present.